Parasites use Trojan horse tactic

25 November 2014

Parasites use Trojan horse subterfuge to suppress the immunity of their victims when causing infection, according to a study funded by the Wellcome Trust.

The finding, which shows a new trick parasites can play, paves the way to possible treatments for infectious diseases and allergies.

Scientists at the University of Edinburgh have shown that parasites are able to secrete tiny sealed packages of genetic material into the cells of their victims, in order to suppress the immune response to infection.

The packages, known as vesicles, mimic those that are produced naturally in most organisms to carry out everyday functions such as transporting nutrients and chemical messages to and from cells.

The parasite uses vesicles to hide its material inside a seemingly friendly exterior, like a Trojan horse.

The study was carried out on a parasite found in mice and showed that the material in the packages is able to interact with the mouse's own genes.

It manipulates the cell's machinery to suppress products linked to immunity, so reducing resistance to infection.

The researchers say the discovery could inform new strategies for treating diseases caused by parasitic worms, which affect hundreds of millions of people and animals.

The findings also offer a possible way to treat allergies, such as hayfever, because the immune mechanism that parasites block is also linked to allergic reactions.

The genetic material from the parasites can also be detected in human blood, suggesting that this could be used as a test to detect infection in people.

Ongoing studies are looking into whether other parasites and viruses use this same strategy.

Dr Amy Buck of the University of Edinburgh said: "We can see for the first time that parasites can use packages to sneak their material into the cells of other organisms. We now can develop ways to target this with implications for the billions of people and animals at risk of infectious diseases and allergy."

The paper, Exosomes secreted by a nematode parasite transfer small RNAs to mammalian cells and regulate genes of the innate immune system, is published in Nature Communications.

  • A Wellcome Trust-funded study shows that parasites use a Trojan horse tactic to suppress the immunity of their victims - by using vesicles, or tiny sealed packages, that mimic those naturally produced in most organisms to get their genetic material into host cells undetected.
  • It's hoped that the findings, from scientists at the University of Edinburgh, will lead to new treatments for parasitic worms as well as allergies such as hayfever - because the immune mechanism the parasites block is also linked to allergic reactions.